In the 7th year of this grant, we will continue studies of left ventricular performance under different chronic pressure overload states. We will produce a chronic pressure overload state with a ligature on the ascending aorta; then we will measure left ventricular performance using biplane ventriculography, myocardial blood flow with radioactive microspheres, and myocardial oxygen consumption from coronary A-V Oxygen difference, and flow. We will correlate function, flow, and oxygen consumption at normal and high heart rates. We will also produce a chronic volume overload by surgically inserting a shunt between the aorta and left atrium. This chronic volume overload model will be studied as described above, with the addition of a partial stenosis of a coronary artery. Both studies closely model human disease states, and the data will be immediately applicable to these conditions in man.